A Mittenless Autumn, for Better and Worse

Published: December 23, 2001

Correction Appended

(Page 3 of 3)

Dr. Edward S. Sarachik, a professor of atmospheric sciences at the University of Washington in Seattle, said it was especially significant that 2001 had proved so warm. Usually, the conditions in a single year are discounted by climate scientists because weather conditions vary naturally over short time spans, pushed this way or that by unpredictable shifts in sea temperatures and wind patterns.

But in 2001 there was no such push -- in particular, no sign of El Niño, the ocean condition in which unusually warm waters spread across the Pacific. El Niño has exerted a powerful influence in many other recent unusually warm years, including 1998, the warmest year on record. But this year, the Pacific has just emerged from the opposite, cooler condition, La Niña.

A milder climate has short-term and long-term consequences for everything from water supplies to beaches.

Higher temperatures, for example, mean reduced snow melt from the Sierras, on which California's reservoirs depend.

''As the earth is warming, less of our precipitation will be snow and more will fall as rain, and that has a whole series of problems for us,'' Dr. Gleick said. ''It means we're going to get more runoff in the winters when we're most worried about floods. And at the other end it means our spring and our summer runoff is going to be reduced -- and that's when we need it most.''

In Alaska -- and much of Siberia -- the annual mean temperature has risen 3 to 5 degrees over the last 30 years, said Prof. Gunter Weller, director of the Cooperative Institute for Arctic Research at the University of Alaska at Fairbanks.

''There's no doubt over all that the Arctic has warmed pretty substantially, and that it's causing serious problems,'' Professor Weller said. Among the effects are increased coastal erosion from melting glaciers, which have raised the sea level in the region, and thawing in the permafrost that has wreaked havoc with roads and could eventually damage structures like the 800-mile-long trans-Alaska pipeline.

Elsewhere, continued warming could produce rising sea levels and more frequent and more severe storms. Seas will rise with temperatures because water expands as it warms, and because melting terrestrial ice will send water flowing into oceans. Hurricanes draw their energy from the heat in ocean waters, so warming could make them more frequent and more powerful.

The consequences would be most serious for the East and Gulf Coasts, which are lined with low-lying barrier islands. A rise of one to three feet in the sea level, which many scientists predict by the end of this century, could send sea water 100 feet or more inland on these stretches of coast, in communities where the federal government is spending tens of millions of dollars a year to pump sand onto shrinking beaches.

The new evidence of human-caused warming comes as the Bush administration is turning its attention back to climate change, which it had approached with skepticism and a determination to choose no remedies that might hinder the use of coal, oil and other fossil fuels.

Most notably, last March Mr. Bush rejected the Kyoto Protocol, the first international agreement that would require industrialized countries to cut emissions of greenhouse gases or face penalties. The last details were approved by almost every other major country at a meeting in November, although the treaty still awaits ratification.

In the next month or two, the Commerce Department, answering a request by Mr. Bush last summer, is planning to issue a new research plan aimed at improving United States climate monitoring and modeling efforts.

Senator Ted Stevens, Republican of Alaska, is one of many from both parties in Congress seeking significant new efforts, especially climate research.

''I have asked that consideration be given in the coming budget to increase activities,'' Mr. Stevens said, ''to zero in on places where they know they can get some firm data and get some firm predictions.''

Others in Congress are proposing bills to limit releases of carbon dioxide from power plants, but Mr. Bush rejected such a move last spring.

While officials debate how to deal with the phenomenon, temperatures continue to climb.

Along with whatever warming might be happening because of human activities, federal scientists say, the Pacific is emerging from its most recent cool spell and the warm waters of another El Niño are getting ready to spread.

Photos: Just days before Christmas, the grass at the New York Botanical Garden was still in need of mowing. (Suzanne DeChillo/The New York Times)(pg. A1); It was warm enough for short sleeves when Joseph Privatelli of Brooklyn put up his Christmas decorations. (James Estrin/The New York Times); The warm fall weather delayed the start of the ski season at Sugarbrush in Warren, Vt., and other ski resorts. (Associated Press); Two calliope hummingbirds turned up in Manhattan a month ago. Ordinarily, the birds are wintering in Mexico this time of year. (Deborah Allen)(pg. A28) Chart: ''In 2001, It Got Warmer'' Symbols show the difference between 2001 temperatures (Jan.-Nov.) and 1961-1990 averages. Readings are for areas 5degrees latitude by 5degrees longitude; data is not available for areas with no symbols. Chart: ''But the Trend Started Decades Ago'' Based on data throughout the year and projecting temperatures for the last two weeks of December, 2001 is likely to be the second-warmest year on record. The average annual global temperature is projected to be 57.8degreesF, which is 0.9degrees above the 1880-2000 long-term average. 1998 was the warmest year on record, with an average temperature of 58.1degrees Other years in the five warmest: 1997, 1995 and 1990. 2001 is projected to be the second-warmest year, with an average temperature of 57.8degrees 1880-2000 average global temperature: 56.9degrees Graph tracks temperatures from 1880-2000. (Source: Jay Lawrimore and Scott Stephens, National Climatic Data Center) Map of World shows degree changes. (pg. A28)

Correction: January 1, 2002, Tuesday A picture caption on Dec. 23 with a front-page article about the unusually warm fall weather misspelled the name of a ski resort in Warren, Vt., and omitted the date of the photograph. The resort is Sugarbush, not Sugarbrush. The picture was made on Dec. 4, when slopes were barren and lifts empty. By the time of publication, about 20 inches of snow had fallen, allowing skiing to begin.